Not high-fashion, not high-brow, just a high-necked shirt.
It's pronounced truh-del-nick btw. And it just stands for turtleneck. We're not here to announce the turtleneck is back, but we are here to remind you they look really good. They always have, but for guys they've been wrapped in stigma. Just because you're not Jobs or Drake ora fashionista doesn't mean you can't get away with rocking a turtleneck.